The email referenced comments made by President Obama about the GOP field’s heavy criticism of the CNBC presidential debate. Speaking at a Democratic fundraiser in New York, Obama mocked the candidates for taking a hard line on foreign policy yet being unable to “handle a bunch of CNBC moderators.”

“If you can’t handle those guys, then I don’t think the Chinese and the Russians are going to be too worried about you,” the president said.

Santorum countered Obama’s jab by saying he has “taken on” formidable forces including ISIS and Iran.

“They know who I am and I know who they are!” he wrote.

The former Pennsylvania senator is known for advocating an aggressive approach to terrorism. In May, he proposed that the U.S. bomb ISIS “back to the 7th Century.”

Santorum also suggested he was up to taking on challengers closer to home, pointing to his appearances on various liberal-leaning talk shows. One example was his July visit to MSNBC’s “Rachel Maddow Show,” in which he insisted that the Supreme Court decision legalizing gay marriage was illegitimate. Though Maddow told him he was “fundamentally wrong on civics,” Santorum said he “won” the argument.

The Santorum campaign did not immediately respond to multiple requests for comment.

ABOUT THE AUTHOR

Allegra Kirkland is a New York-based reporter for Talking Points Memo. She previously worked on The Nation’s web team and as the associate managing editor for AlterNet. Follow her on Twitter @allegrakirkland.